One of the module that already supports the systemd-confinement module
is public-inbox. However with the changes to support DynamicUser and
ProtectSystem, the module will now fail at runtime if confinement is
enabled (it's optional and you'll need to override it via another
module).
The reason is that the RootDirectory is set to /var/empty in the
public-inbox module, which doesn't work well with the InaccessiblePaths
directive we now use to support DynamicUser/ProtectSystem.
To make this issue more visible, I decided to just change the priority
of the RootDirectory option definiton the default override priority so
that whenever another different option is defined, we'll get a conflict
at evaluation time.
Signed-off-by: aszlig <aszlig@nix.build>
Our more thorough parametrised tests uncovered that with the changes for
supporting DynamicUser, we now have the situation that for static users
the root directory within the confined environment is now writable for
the user in question.
This is obviously not what we want and I'd consider that a regression.
However while discussing this with @ju1m and my suggestion being to
set TemporaryFileSystem to "/" (as we had previously), they had an even
better idea[1]:
> The goal is to deny write access to / to non-root users,
>
> * TemporaryFileSystem=/ gives us that through the ownership of / by
> root (instead of the service's user inherited from
> RuntimeDirectory=).
> * ProtectSystem=strict gives us that by mounting / read-only (while
> keeping its ownership to the service's user).
>
> To avoid the incompatibilities of TemporaryFileSystem=/ mentioned
> above, I suggest to mount / read-only in all cases with
> ReadOnlyPaths = [ "+/" ]:
>
> ...
>
> I guess this would require at least two changes to the current tests:
>
> 1. to no longer expect root to be able to write to some paths (like
> /bin) (at least not without first remounting / in read-write
> mode).
> 2. to no longer expect non-root users to fail to write to certain
> paths with a "permission denied" error code, but with a
> "read-only file system" error code.
I like the solution with ReadOnlyPaths even more because it further
reduces the attack surface if the user is root. In chroot-only mode this
is especially useful, since if there are no other bind-mounted paths
involved in the unit configuration, the whole file system within the
confined environment is read-only.
[1]: https://github.com/NixOS/nixpkgs/pull/289593#discussion_r1586794215
Signed-off-by: aszlig <aszlig@nix.build>
these changes were generated with nixq 0.0.2, by running
nixq ">> lib.mdDoc[remove] Argument[keep]" --batchmode nixos/**.nix
nixq ">> mdDoc[remove] Argument[keep]" --batchmode nixos/**.nix
nixq ">> Inherit >> mdDoc[remove]" --batchmode nixos/**.nix
two mentions of the mdDoc function remain in nixos/, both of which
are inside of comments.
Since lib.mdDoc is already defined as just id, this commit is a no-op as
far as Nix (and the built manual) is concerned.
Certain software stacks have no support for OpenSSL non-standard PEM format and will fail to use
our NixOS CA bundle.
For this, it is necessary to fallback on a 'compatibility' bundle which will contain no additional
trust rules.
Signed-off-by: Raito Bezarius <masterancpp@gmail.com>
Would otherwise fail with
```
error: A definition for option `systemd.services.auditd.conflicts."[definition 1-entry 1]"' is not of type `string matching the pattern [a-zA-Z0-9@%:_.\-]+[.](service|socket|device|mount|automount|swap|target|path|timer|scope|slice)'. Definition values:
- In `/nix/store/x2khl2yx0vz2i357x7mz5xm1kagql8ag-source/nixos/modules/security/auditd.nix': "shutdown.target "
```
